Final answer:
Oxygen concentrations of 6-8 percent can lead to hypoxia, causing fatigue, headaches, and confusion due to insufficient oxygen transport by hemoglobin. The body has a limited tolerance to low oxygen levels and requires an adequate oxygen partial pressure to prevent tissue damage. Hemoglobin and synthetic oxygen carriers help maintain higher dissolved oxygen concentrations to support body functions.
Step-by-step explanation:
When the body is exposed to oxygen concentrations of 6-8 percent, it can lead to hypoxia, which can cause symptoms such as fatigue, headaches, and confusion. The partial pressure of oxygen (PO2) in the alveoli needs to be at a sufficient level to maintain a high percent oxygen saturation of hemoglobin. Hemoglobin serves as an oxygen carrier and facilitates the transport of oxygen from the lungs to the tissues.
The body cannot tolerate low oxygen environments due to its continuous consumption to maintain energy homeostasis. When exposed to low PO2, fewer oxygen molecules dissociate from hemoglobin, which can result in an insufficient supply of oxygen to the tissues. This can exacerbate hypoxia symptoms and have more serious effects, potentially being fatal or causing permanent damage.
Synthetic oxygen carriers and blood substitutes with high Henry's law constants have been developed as emergency replacements to increase dissolved oxygen concentrations. However, the most effective natural oxygen carrier in humans is hemoglobin, which increases O2 concentration by almost a thousand times more than dissolved O2 alone would allow.